Sunday, April 22, 2012

A biological refugium

Well, we’re recently back from McGill’s spring CEEB (Conservation,
Ecology, Evolution, and Behavior) retreat, which was a blast. It was
held at McGill’s field station at Mont
St-Hilaire:

That’s Lac Hertel, the lake that is rather curiously perched in the
middle of the ring of hills that comprises the “Mont”. (It rather
looks like a volcanic caldera lake, but that is not the case; the Monteregian
Hills are igneous intrusions, not extinct volcanoes, and the lake
was formed by glacial erosion.) The Gault House where the retreat was
held is the building visible on the lake shore. Nice digs.

Below, Krista Oke and Shahin Muttalib write a bit about the research
they presented at the retreat; but first, trivia! These questions were
prepared by Gregor Fussman to test the wits of the assembled graduate
students. Answers are at the bottom of the post.

Question 1. What happened in which year? (Match each lettered
year with one of the listed events.)

a) 1821, b) 1822, c) 1831, d) 1851

Events:

“Moby-Dick” published
McGill University founded
Hieroglyphs on the Rosetta Stone deciphered
Voyage of the Beagle starts

The degree to which gene flow can constrain adaptation is still an open
question, and inferring causality from correlation studies between
levels of divergence and levels of gene flow isn’t quite convincing
enough. Another approach is to measure selection in a site where we
expect to find maladaptation: maladapted populations should experience
higher selection. With this in mind, I tagged hundreds of fish over two
winters and two summers in Misty Outlet and Misty Inlet, hoping to
estimate natural selection on body shape. Since good selection
estimates are dependent on capturing as many surviving fish as
possible, I first estimated survival and recapture probability. It
turns out recapture probability was higher in the outlet, so selection
estimates are more precise for the outlet. Survival probability was
lowest in the winter in the outlet, which is also where I found the
highest selection intensity. I am using two metrics to measure total
selection intensity: one for overall selection due to the traits that I
have measured, and a measure of relative selection taking into account
selection on unmeasured traits. So while the outlet has higher overall
selection in the winter, it also has more selection due to other
traits. At the level of particular traits, I have found effects for fin
positioning, head size, body depth and position of the pelvic spine.
These are traits that contribute most to total selection intensity,
show the strongest selection gradients, and also show selection in the
expected direction, i.e.: towards the more adapted inlet trait values.
This spring the stickleback team will be wading through the streams for
one last season of data to confirm if selection is indeed consistently
higher over the winter in the outlet. Watch out for those Misty Lake
zombies!

The study of parallel evolution is important because it provides
evidence for a deterministic role of natural selection in evolution and
speciation, but parallel evolution is much more often inferred from
field studies. Laboratory studies on parallelism have been relatively
rare. Since plasticity could affect parallelism in several ways, the
use of common garden studies could provide much insight into this
process. A genetic basis for parallelism has been detected in some
traits in one lake-stream stickleback pair, the Misty Lake pair,
although plasticity was also detected. My MSc work asks whether there
is a genetic or plastic basis to parallel evolution in three other
watersheds on Vancouver Island. I currently have first generation lab
fish growing in a common garden setup in our lab at McGill, but so far
no results to report. I will be part of the field crew Shahin mentioned
heading back to BC soon, where we will also be creating crosses to
supplement the fish I have in the lab now. No one warned me about the
zombies, though!

If you now have the warm, triumphant glow of a life spent immersed in
the companionship of friends who love biology – but you also have a
hangover and are in desperate need of a shower – then this post has
given you a taste of what the CEEB retreat is like. Hey, at least we
didn’t bring up meme-sex this time!

BUT, the trivia wasn’t quite over. A surprise last
question moved the team rankings around, so a final challenge was
issued. It was a combination of physical speed (running around the
building twice), teamwork, memorization, and knowledge of your field.
What was most interesting about it was that the team of the person
running had to come up with a canonical paper in the field of ecology
and evolution. The team would whisper it to the runner, and then they
had to write it on a blackboard. This was all fine and good, but
several interesting things came out:

1) We all know the authors and years, but do you know the exact title
of papers that are important in your field?

2) Do you know which ones are books, and which ones are articles?

3) How do you weigh the relative importance of different papers?

4) Did you know that marker caps, manipulated with excessive haste, can
cause wounds?

It was an interesting and contentious final round. Of the articles the
teams came up with, the citation counts for the articles ranged from 6
(Hendry and Gonzalez – Whither adaption?) to 12,528 (Fisher – The
genetical theory of natural selection). Fisher’s ought to have been
eliminated because it is a book, not an article, but that felt like too
large a penalty, so the top two teams ended up splitting the prize: a
bottle of rare Hendry wine.

Food for thought: at what point does an article become canonical or
seminal in your field, and how might this be measured? H-index of the
authors? Average citations per year? Total citations? First author
awesomeness?

PS. Kiyoko apologizes for the publishing, subsequent dissapearance, and then reappearance of the post. In an attempt to add pictures, she managed to edit the draft to nothing. After much teeth gnashing, luck, and hair pulling, she realized Blogger plays nicest with Chrome. She should have known like begets like. Thanks to those who never close their browser windows and were able to send Kiyoko the text so she could ressurect this post. I think the original post has gone to hang out with the Misty Lake zombies. What fun!